On Tue, 2012-04-17 at 15:49 +0200, Janusz Krzysztofik wrote:> A call to request_mem_region() has been introduced in the omap-gpio> driver recently (commit 96751fcbe5438e95514b025e9cee7a6d38038f40,> "gpio/omap: Use devm_ API and add request_mem_region"). This change> prevented the Amstrad Delta NAND driver, which was doing the same in> order to take control over OMAP MPU I/O lines that the NAND device hangs> off, from loading successfully.> > There is another driver, omap-keypad, which also manipulates OMAP MPUIO> registers, but has never been calling request_mem_region() on startup,> so it's not affected by the change in the gpio-omap and works correctly.> > Drop request_mem_region() call and related bits from ams-delta NAND> driver.> > Created and tested against linux-3.4-rc3.> > Signed-off-by: Janusz Krzysztofik <jkrzyszt@tis.icnet.pl>

How about race conditions? Where is the guarantee that these 2 driverswon't affect each other when doing I/O at the same time to the same HWresources?